Correlation analysis of Shiga toxin-producing Escherichia coli shedding and faecal bacterial composition in beef cattle.

AIMS: The objectives of this study were to investigate the correlations between Shiga toxin-producing Escherichia coli (STEC) shedding and faecal microflora in beef cattle and to identify functional species that might be used for STEC control. METHODS AND RESULTS: Faecal samples were collected from 110 calves and 92 dams. The number and prevalence of STEC were determined using CHROMagar™ STEC; denaturing gradient gel electrophoresis (DGGE) was employed to analyse faecal bacterial composition. Six-month-old calves had the highest STEC shedding levels (3.03 ± 1.41 Log CFU g(-1)) and prevalence (95.5%). Both the number and prevalence decreased significantly as the calf age increased (P < 0.05). The DGGE analysis showed that faecal bacterial diversity increased, while cattle ages increased and STEC shedding levels decreased. Significant correlations between STEC shedding, cattle age and bacterial compositions were observed by redundancy analysis (P < 0.05). T-value biplots and sequencing results indicated that butyrate-producing bacteria (BPB) negatively correlated with STEC shedding. CONCLUSIONS: Higher STEC shedding levels and prevalence were associated with younger cattle age, lower faecal bacterial diversity and lower BPB levels. SIGNIFICANCE AND IMPACT OF THE STUDY: Butyrate-producing bacteria in GI tract might serve as an option for the future development of STEC shedding control strategy.

Southern Section Interdisciplinary Beef Cattle Symposium: Forage and co-product systems for stockers in the South: have fundamental shifts in markets changed the optimal system?

Stockering calves in the southern United States has been an economically viable enterprise for decades. Historically, the system that yielded the best opportunity for profitability was to purchase lightweight calves (130 kg to 220 kg) in autumn, add 100 to 200 kg of BW gain, and sell them in the spring. In most years, the value of the BW gain was worth more than the cost of BW gain in this system. With the exponential price increases in feed, fuel, and fertilizer during 2008 and the significant increase in cattle prices, it is prudent to assess the potential for continued profitability in this segment of the beef industry. Evaluation of 37 grazing experiments indicated that the forage systems most likely to result in inexpensive costs of BW gain for stocker calves involve tall fescue with legumes or ryegrass with small grains. Even with increased input prices, these systems still yield economical BW gain for stocker calves. Likewise, many diets can be blended to produce ADG of 1 kg using co-products that are abundant across the South. With many of these co-products, the most important performance factor in determining their value is G:F. In several experiments, DMI has exceeded 3% of BW in stocker calves, and the resulting G:F has been less than desirable. Several experiments have reported G:F of 0.13 to 0.16, resulting in economical BW gain, whereas some experiments have reported G:F as low as 0.09, which could result in BW gain that costs more to produce than it is worth. From 1979, the value of BW gain for stocker calves in Alabama has averaged US$1.05/kg. However, in the last 3 yr, the value of BW gain has risen to $2.32/kg. Fundamental shifts in feed, fuel, and fertilizer prices experienced in the United States between 2005 and 2010 have markedly changed the amount of capital needed to purchase several hundred stocker calves and to provide adequate feedstuffs for BW gain. However, the value of BW gain associated with producing feeder calves from those stockers has experienced a concomitant increase. The optimal system still uses high-quality cool-season forages and supplementation with co-product feeds. With this system, a significant margin of profit still exists for the Southeastern stocker cattle production system.

Finishing steers on winter annual ryegrass (Lolium multiflorum Lam.) with varied levels of corn supplementation I: effects on animal performance, carcass traits, and forage quality.

Crossbred steers (n = 72) were selected to study forage-based finishing systems using winter annual ryegrass (Lolium multiflorum Lam.) with varying levels of grain supplementation. In December, cattle were allotted to 1 of 6 treatments consisting of ryegrass pasture (1 ha) with whole shell corn supplemented at 0.0% (0.0), 0.5% (0.5), 1.0% (1.0), 1.5% (1.5), and 2.0% (2.0) of BW, or an ad libitum mixed-ration grain diet in a drylot. Steers were randomly assigned to pens of 4 with pen serving as the experimental unit. Cattle were slaughtered by pen when average pen backfat thickness (as measured by real-time ultrasound) reached approximately 0.64 cm. Forage samples and disk meter height were taken from ryegrass paddocks on a monthly basis to determine forage quality and mass. Live animal performance, carcass traits, proximate analysis, Warner-Bratzler shear force, and sensory characteristics from the LM of the rib section were analyzed. Increasing the amount of grain in the diet of finishing cattle resulted in a linear decrease (P < 0.05) in days on feed and a linear increase (P < 0.05) in ADG, preliminary yield grade, final yield grade, flavor intensity, and beef flavor. Forage DM mass increased with each incremental increase in grain added to the grazing diets. Quality of forage was not (P > 0.05) affected by adding grain to the diet. Adding corn to the diet of cattle being finished on forage improved animal performance and decreased forage utilization characteristics in addition to improving the flavor characteristics of beef.

Carcass, sensory, fat color, and consumer acceptance characteristics of Angus-cross steers finished on ryegrass (Lolium multiflorum) forage or on a high-concentrate diet.

Fall-born Angus-cross steers (n=30) from 1 of 2 sires, were randomly assigned to either an 85% corn, 7.5% cotton-seed hulls, and 7.5% vitamin/mineral/urea supplement diet (GRAIN), 100% ryegrass grazing (RG), or ryegrass grazing then the GRAIN diet for 94d (RG/GRAIN). USDA Yield Grade of steers finished on either the GRAIN or RG/GRAIN regimens were higher (P<0.02) compared to those finished on RG. Marbling score and USDA Quality Grade did not differ (P=0.21 and 0.12, respectively) among the three finishing regimens. Yellowness (b(∗)) values of the subcutaneous fat from both strip loins (SL) and ribeye (RE) rolls was lowest (P<0.05) in cuts taken from steers finished on GRAIN. Subcutaneous fat of both SL and RE had lower L(∗) and hue angle values, and higher a(∗) and b(∗) values before trimming than after the fat was trimmed to 0.3cm. Initial and sustained tenderness scores of SL from steers finished on GRAIN were higher when compared to RG/GRAIN or RG regimens (P<0.05). Flavor intensity and beef flavor scores were higher (P<0.05) for SL from GRAIN- or RG/GRAIN-finished steers compared to RG-finished steers. GRAIN SL had lower (P<0.05) WBSF values than RG, but similar (P>0.05) to RG/GRAIN. Trained sensory tenderness and flavor scores and WBSF values for RE were not affected by finishing regimen (P>0.05). GRAIN steaks had a higher consumer overall acceptability score, average price/kg, and rank (P<0.05). While carcass, fat, and sensory disadvantages were present in RG cattle, the overall magnitude of the differences compared to GRAIN cattle was fairly small.

The semantic Simon effect in Tourette's syndrome and obsessive-compulsive disorder.

Core symptoms of Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD) may be attributed to an impairment in inhibitory control. Neuropsychological studies have addressed inhibition in both disorders, but findings have been inconsistent. The aim of this study was to examine cognitive inhibition, using a semantic Simon effect paradigm, in patients with TS and OCD. Furthermore, to address comorbidity a group of TS+OCD patients was also examined. Results indicated that patients with TS and OCD were affected by the inhibitory components of the task. TS groups performed similarly to controls on simple and choice RT tasks, but were particularly compromised as increasingly complex inhibitory demands were imposed. OCD patients were slower and committed more errors than controls, especially in the more cognitively demanding conditions, and were particularly disadvantaged by incongruent stimulus-response compatibilities. Findings implicate possible fronto-striatal dysfunction, are consistent with previously reported inhibitory deficits in TS and OCD, and support the theory that comorbid TS+OCD is more closely linked to pure TS than OCD.

Local-global processing in obsessive-compulsive disorder and comorbid Tourette's syndrome.

Neuropsychological and neuroimaging studies implicate attentional difficulties in obsessive-compulsive disorder (OCD), but results are inconsistent due possibly to sample heterogeneity and lack of control of comorbid disorders, such as Tourette's syndrome (TS). Nevertheless, it has been suggested that OCD symptomatology may be a result of over-focused attention at a local level. Therefore, this study aimed to examine the ability of OCD patients (pure and comorbid OCD + TS) to process local and global stimuli. Using a local-global paradigm, participants were required to respond to the directed level (local or global) of various stimuli. Results indicate that pure OCD participants were impaired on the global task, whereas comorbid OCD + TS participants had difficulty processing local information. Results are consistent with previously reported lateralisation anomalies and suggest that OCD negatively affects the ability to process hierarchically presented stimuli.

Rice mill feed as a replacement for broiler litter in diets for growing beef cattle.

The efficacy of replacing broiler litter with rice mill feed was evaluated in four experiments. In Exp. 1, 40 predominantly Angus steers (initial BW = 277+/-18.2 kg) were fed four dietary treatments for 112 d (five steers per pen; two pens per diet). Dietary treatments (DM basis) were as follows: 1) 47% broiler litter:53% corn; 2) 60% rice mill feed:40% corn; 3) 50% rice mill feed:50% corn; and 4) 40% rice mill feed:60% corn. All diets, along with bermudagrass hay, were fed free choice. Daily gains were faster (P < 0.10) for the 50:50 and 40:60 diets (1.26 and 1.30 kg/d, respectively) than for the broiler litter diet (0.89 kg/d). Daily DMI was less (P < 0.10) by steers consuming rice mill feed-based diets than by those consuming broiler litter-based diets. In Exp. 2, 16 Angus x Charolais steers (initial BW = 277+/-22.7 kg) were fed the same four diets used in Exp. 1 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was not different (P > 0.10) among diets. Nutrient digestibilities did not differ among diets (P > 0.10). In Exp. 3, 40 Continental cross steers (initial BW = 257+/-21.3 kg) were fed one of four dietary treatments for 112 d (five steers per pen; two pens per diet). On a DM basis, diets were as follows: 1) 47% broiler litter:53% soyhulls; 2) 70% rice mill feed:30% soyhulls; 3) 60% rice mill feed:40% soyhulls; and 4) 50% rice mill feed:50% soyhulls. All diets, along with bermudagrass hay, were fed free choice. Daily gains were less (P < 0.05) for the broiler litter diet than for the 60:40 and 50:50 diets (1.05, 1.16, and 1.28 kg/d, respectively), and steers fed the broiler litter diet consumed less DM than did steers fed the varying rice mill feed-based diets (P < 0.10). In Exp. 4, 16 Angus x Charolais steers (initial BW = 292+/-21.1 kg) were fed the same four diets as in Exp. 3 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was less (P < 0.01) for the broiler litter diet (5.0 kg/d) than for the 70:30, 60:40, and 50:50 diets (7.8, 7.9, and 7.9 kg/ d, respectively). Digestibilities for DM, OM, and ADF did not differ (P > 0.10) among treatments; however, CP digestibility was greatest (P < 0.10) for the 60:40 diet, and NDF digestibility was least (P < 0.10) for the 70:30 diet. Rice mill feed can be used to replace broiler litter to formulate low-cost diets for stocker calves. Soyhulls and corn can be blended with rice mill feed to produce acceptable backgrounding diets for growing beef calves.

Antioxidant status affects color stability and tenderness of calcium chloride-injected beef.

The objectives of this study were to determine whether vitamin E supplementation influences color and tenderness of beef injected with calcium chloride. Market heifers (n = 12) were fed a standard finishing diet with minimal levels of vitamin E (NE group). Another 12 market heifers were fed the NE diet with the inclusion of 1,000 IU/d of DL-alpha-tocopherol per animal for the last 125 d on feed (E group). Animals were slaughtered after 125 d on the diets and upon reaching an ultrasound backfat thickness > 10 mm. Half of the longissimus muscles from each treatment group (NE and E) were pumped to 10% over the original weight with 250 mM CaCl2 (Ca) at 24 h postmortem. Remaining muscles (NE and E) were pumped to 10% over the original weight with water (NC) at 24 h postmortem. After equilibrating overnight, steaks (2.54 cm) were overwrapped with O2-permeable film and stored for 7 d after injection. Hunter "L," "a," and "b" values were obtained each day of storage. Trained panelists evaluated color on d 1, 4, and 7 after injection. 2-Thiobarbituric acid-reactive substances (TBARS) values were measured on d 1 and 7 after injection. Warner-Bratzler (W-B) shear force values and trained sensory panel evaluations at 1, 3, and 7 d after injection were obtained. Immunoblotting techniques were used to monitor the 30-kDa degradation product of troponin-T at 1, 3, and 7 d after injection. At 4 d after injection, E/Ca steaks were the least discolored (P < 0.05). The E/Ca steak TBARS values were not significantly different from values for NE/NC steaks at 7 d after injection, whereas NE/Ca steaks had greater (P < 0.05) TBARS values after 7 d following injection compared with all other groups. Treatment with Ca resulted in higher off-flavor scores (P < 0.05). The E/Ca samples had the most rapid tenderization and proteolysis of all treatment groups. Warner-Bratzler shear values were lower in the E/Ca samples than in the E/NC samples at 1, 3, and 7 d after injection (P < 0.05). No difference in shear force was noted between NE/Ca and NE/NC samples at any time point. No difference in sensory tenderness was noted between NE/Ca and NE/NC samples at 1 d after injection. However, Ca-injected samples (NE/Ca and E/Ca) were rated as being significantly more tender than their uninjected counterparts (NE/NC and E/NC) at 3 and 7 d after injection. Injection of CaCl2 may result in more rapid and immediate tenderization if beef from animals supplemented with vitamin E is used. Vitamin E incorporation into muscle tissue may potentiate the action of exogenously added calcium by protecting the calpains from oxidation.

In vitro ruminal disappearance of fumonisin B1 and its effects on in vitro dry matter disappearance.

Fumonisins were produced by inoculating corn with Fusarium moniliforme M-1325 and incubating for 5 w. Fumonisin B1 (FB1) concentration determined by high performance liquid chromatography was 5,087 ppm. Ruminal fluid inoculum obtained from 2 ruminally cannulated steers and tubes containing 0, 50 or 100 ppm of FB1 were incubated in vitro with ruminal fluid and artificial saliva for 72 h in a 39 C oscillating incubator. Supernatant was analyzed for FB1 concentration, and in vitro dry matter disappearance (IVDMD) was calculated in the remaining precipitates. There was minimal degradation of FB1 by ruminal microbes (about 10%) irrespective of concentration of FB1 used when incubated for the 72 h. No differences in IVDMD rates, were found between treatments, and the rates were normal, indicating that microbial efficiency was unaffected by the presence of FB1 at diet concentrations up to 100 ppm.

Effects of fumonisin B1-contaminated feeds on weanling angora goats.

Two diets containing no (<1.0 mg/ kg) or 95 mg of fumonisin B1 (FB1)/kg were fed to eight weanling Angora goats for 112 d. Dry matter intake, apparent nutrient digestibilities, serum chemistry profiles, sphingolipid concentrations, and persistency of FB1 in tissues were evaluated. No differences (P>.10) were found between control and treated goats in terms of DMI, apparent nutrient digestibilities, or ADG. Elevated concentrations (P<.10) of blood-borne enzymes such as aspartate aminotransferase, lactate dehydrogenase, and gamma glutamyl transpeptidase and increased concentrations of cholesterol and triglycerides indicated mild liver damage and kidney dysfunction in treated goats. Linear relationships (P<.10) were observed between these serum constituents and duration of FB1 exposure. The sphingolipid analysis of liver, kidney, and heart tissues showed elevated free sphinganine:free sphingosine ratios in the treated group. The elevated sphingolipid ratios were mainly due to increased concentrations of free sphinganine in tissues. However, without serum profile and sphingolipid analyses, fumonisin toxicosis would not have been recognized because treated animals showed no clinical signs of toxicosis throughout the trial. No measurable FB1 was present in liver, kidney, and heart tissues (detection limit of 1 ppm). However, further research is needed to analyze tissues for FB1 or its metabolites with a lower detection limit. In conclusion, goats can be fed for up to 112 d with diets containing 95 mg FB1/kg of diet without any overt signs of toxicosis and also without any effect on live weight gain.

Mineral status in beef cows fed broiler litter diets with cation-anion differences or supplemented with hay.

Two studies were conducted to evaluate mineral status of beef cows consuming broiler litter (BL). During the first study, three diets (hay, BL + corn + hay, and BL + corn + hay + NH4C1) were fed to 45 pregnant cows from December through May to evaluate the effect of decreasing the dietary cation-anion difference (DCAD). Dry matter intake was not affected (P > .05) by treatments. Serum Ca was suppressed (P < .05) in cows consuming BL at 101 d prepartum. Serum hydroxyproline concentrations were suppressed (P < .05) before, at, and after parturition in cows consuming BL, whereas parathyroid hormone concentrations were not influenced (P > .05) by diet. Estimated digestibilities of OM, ADF, NDF, and hemicellulose were decreased (P < .05) for BL diets at midgestation, whereas only the fiber portions of the BL diets were decreased at parturition in BL diets compared with hay. Apparent absorption of Ca was greater (P < .05) for BL diets at midgestation; however, this difference was not observed at parturition. No differences (P > .05) were determined for milk or urine excretion of Ca. For the second study, three diets (hay, BL + corn, and BL + corn + hay) were fed to 48 cows. Serum Ca was suppressed (P < .05) in cows consuming BL diets, and serum hydroxyproline was greater (P < .05) in cows consuming the hay-supplemented diet than in those consuming BL without hay. Lowering the DCAD was not effective in offsetting the serum Ca changes observed; however, supplementing hay may allow for more bone resorption of Ca at a time when cows are in need of increased Ca.

Metoclopramide and (or) cimetidine administration to sheep fed tall fescue.

Fifteen crossbred sheep were assigned randomly to 1 of 5 treatments: endophyte-free fescue diet (EF; 0% infected; 50% hay, 40% seed, 10% molasses); endophyte-infected diet (El; 95% infected; 50% hay, 40% seed, 10% molasses); El + 15 mg metoclopramide/kg body weight, 3 times/w; El + 9.0 mg cimetidine/kg body weight, twice daily; or El + metoclopramide + cimetidine. Both diets contained 92% dry matter (DM), 94% organic matter (OM) and 12% crude protein. All sheep were housed in individual metabolism stalls at 30 C, 14-h light:10-h dark for 18 d. Serum prolactin, respiration rate, heart rate or ear tip, coronary band and rectal temperatures were not affected by any of the treatments after 18 d (P > .10). No differences were detected in nutrient digestibilities except for treatment with metoclopramide + cimetidine, which produced decreased DM, OM and energy digestibilities. Sheep fed the El diet did not exhibit typical fescue toxicosis; therefore, the use of metoclopramide and(or) cimetidine to prevent toxicosis could not be evaluated.

Characterization of toxicosis in sheep dosed with blossoms of sacahuiste (Nolina microcarpa).

To characterize more fully sacahuiste (Nolina microcarpa Watson) toxicosis in sheep and to evaluate benefits of supplemental Zn, sheep were dosed intraruminally with sacahuiste blossoms. In Trial 1, eight fine-wool sheep (47 +/- 2 kg BW) were fed alfalfa hay at 1% of BW daily and dosed intraruminally with inflorescences amounting to 1% of BW daily, in three portions per day, for 10 d. Four sheep were dosed intraruminally with aqueous ZnSO4 (30 mg of Zn/kg BW) daily for 3 d before initial sacahuiste dosing and on alternate days thereafter, and four sheep were untreated with Zn. Toxicosis was evident within 24 h after initial sacahuiste dosage, involving inappetence, depression, hypokalemia, hypophosphatemia, hyperbilirubinemia, and elevated serum enzymes (alkaline phosphatase, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and gamma-glutamyl transpeptidase). One sheep (untreated with Zn) died on d 3. Aqueous ZnSO4 alleviated inappetence and suppressed elevation of serum urea N and creatinine but did not suppress other changes in serum clinical profiles. In Trial 2, sacahuiste inflorescences were ruminally dosed into 12 fine-wool wethers (29 +/- 2 kg BW) in amounts equalling 0, .25, .50, .75% of BW per day, and chopped alfalfa hay was provided at 1.75% of BW per day for 14 d. Sacahuiste inflorescenses dosed at .75% of BW elicited severe toxicosis within 24 h, and dosage at .50 or .25% of BW per day increased (P = .12) serum bilirubin. Ruminal fluid pH, mean particle retention time, and particulate passage rate were not affected (P > .10) by sacahuiste, but ruminal fluid passage rate increased 1.6-fold (P < .10) and ruminal fluid volume decreased by 60% (P < .10) in sheep given inflorescenses amounting to .50% of BW daily. Sacahuiste inflorescenses dosed intraruminally at .75% of BW per day elicited ruminal impaction with severe hepatotoxicosis, and dosages amounting to .50% or .25% of BW per day caused similar trends.

Effects of metoclopramide on steers fed Kochia scoparia hay.

Kochia hay that had elicited mild toxicosis in sheep and cattle when fed for 21 d was fed to young, growing steers to evaluate the efficacy of metoclopramide for preventing kochia toxicosis. Twelve steers (271 +/- 39 kg) were given ad libitum access to Kochia hay for 38 d. Six steers were dosed orally with 15 mg of metoclopramide/kg of BW three times each week in gelatin capsules, and six steers received empty gelatin capsules. Steers were housed in individual outside pens for the first 28 d, then inside in metabolism stalls for the last 10 d. Kochia intake averaged 1.2 +/- .04 and 1.1 +/- .05% of BW throughout 38 d for kochia-fed control and kochia plus metoclopramide-dosed steers, respectively. During the last 10 d, metoclopramide had no effect (P greater than .15) on digestibility of DM, OM, NDF, ADF, or CP. However, metoclopramide reduced N retention (P less than .01; 20 vs 8 g/d). Kochia hay decreased serum prolactin and insulin concentrations (P less than .01) from 12.4 to 1.5 ng/ml and from .53 to .23 ng/ml, respectively. Metoclopramide had no effect (P greater than .50) on prolactin or insulin in steers fed kochia hay. Serum growth hormone was not affected by kochia but was suppressed by metoclopramide in steers fed kochia hay (P less than .07). Serum bilirubin (total and unconjugated) was elevated (P less than .05), indicating early, mild hepatotoxicosis characteristic of kochia toxicosis. Kochia also increased serum concentrations of iron, total protein, albumin, globulin, and creatinine and decreased urea N (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Nutritional and toxicological evaluations of kochia hay (Kochia scoparia) fed to lambs.

Kochia foliage that had tested positive to Dragendorff's reagent (presumptive alkaloids) and had elicited chronic toxicosis when fed to rats was fed to sheep to characterize early stages of kochia toxicosis and evaluate treatments that might improve tolerance. Twelve fine-wool lambs (46 +/- 9 kg BW) were fed chopped kochia hay (35%) mixed with chopped alfalfa hay (65%) for 4 wk. The kochia diet had 14.3% CP and 39.9% ADF. Dry matter intake averaged 3.4% of BW/d. Body weight did not change during 4 wk and blood serum components were not changed from values at the onset. Thereafter, kochia was increased to 50% of diet for five more weeks, during which four treatments were imposed randomly (three lambs/treatment): 1) none; 2) N-acetyl-L-cysteine plus trans-stilbene oxide, 21 and 52 mg/kg of BW, respectively, given i.p. twice weekly; 3) retinyl palmitate, 275 mg, plus alpha-tocopherol, 300 mg/lamb dosed i.m. twice weekly; and 4) zinc sulfate mixed in the feed to provide 500 mg daily. Kochia contained 4.8% oxalate. The diet with 50% kochia had 16% CP and 36% ADF, and digestibility coefficients were 59% for DM, 72% for CP, and 59% for ADF. After 5 wk, blood glucose was elevated slightly, total bilirubin was increased about 1.5-fold (P less than .05), alanine aminotransferase was elevated slightly (P less than .05), and inorganic phosphorus and urea (blood urea N) were diminished (P less than .05); other serum components, including calcium, were unchanged from initial levels (P greater than .10). Treatments had negligible effects for modifying serum signs of mild chronic toxicosis associated with kochia hay fed as 50% of diet.

Altered metabolic hormones, impaired nitrogen retention, and hepatotoxicosis in lambs fed Kochia scoparia hay.

Livestock grazing lush Kochia scoparia (L.) Schrad, sometimes experience BW loss, hyperbilirubinemia, photosensitization, and polyuria. Animals fed kochia hay may exhibit milder or negligible signs of toxicosis but fail to utilize nutrients efficiently. To characterize early aspects of kochia toxicosis and to evaluate prospective treatments, 12 wether lambs (34 +/- 3 kg) were fed prebloom kochia hay (83% OM, 15% CP, and 6.3% total oxalate) and treated as follows: 1) no treatment; 2) drenched daily with aqueous ZnSO4 to provide 30 mg of Zn/kg of BW); 3) injected i.p. twice weekly with N-acetyl-L-cysteine (CYS) in saline (21 mg/kg of BW) plus trans-stilbene oxide (TSO) in corn oil (27 mg/kg of BW); and 4) treated as 2) plus 3). Treatments were imposed factorially (2 x 2) with three lambs per treatment. Kochia intake (ad libitum) averaged .57 kg/d (1.7% of BW) for 80 d, and digestibility of DM and CP were 44 and 59%, respectively, at wk 4, but BW loss was severe (6 to 11 kg/lamb). After 14 d, serum insulin and prolactin were decreased (P less than .05) below initial values (.48 to .11 and 102 to 28 ng/ml, respectively). Serum somatotropin increased (P less than .05) from 4.5 to 6.8 ng/ml at 4 wk. Serum total bilirubin increased threefold at 3 wk (P less than .05) and declined slightly thereafter through 10 wk. Early changes in serum enzymes reflected mild hepatotoxicosis without cholestasis, whereas histopathology (at 80 d) showed diffuse hepatocyte swelling and nephrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum constituents and metabolic hormones in sheep and cattle fed Kochia scoparia hay.

Kochia scoparia (L.) Schrad. is a prospective forage crop for arid areas, although its potential value is constrained by occasional toxicity that may involve alteration of metabolic hormones. The present research compared serum clinical profiles and metabolic hormone concentrations in steers and wethers fed kochia hay (85% OM, 13% CP, 45% ADF, and 6.3% total oxalate) to those of suitable controls that were pair-fed equal amounts of DM as alfalfa hay (91% OM, 13% CP and 42% ADF). Eight steers (240 +/- 2 kg BW) that were pair-fed kochia or alfalfa hay for 21 d had similar levels of serum insulin (INS) or somatotropin (GH), but kochia lowered prolactin (PRL) (6.0 vs 118 ng/ml; P = .14). Kochia hay did not elevate serum bilirubin at d 21 in these steers; however, lactic dehydrogenase and aspartate aminotransferase activities were elevated 1.3-fold (P less than .05). Ten fine-wool wethers (29 +/- kg BW) pair-fed kochia or alfalfa hay for 21 d had similar levels of PRL and INS at d 0, 5, 10, and 21; however, GH was lower in wethers fed kochia at d 5 (P less than .05) and somewhat lower at d 10 and 21. Kochia elevated serum unconjugated bilirubin 1.25-fold over pair-fed controls (P = .06) and increased (P less than .05) activities of aspartate and alanine aminotransferases. Metabolic hormone responses to kochia hay differed in steers vs wethers during undemutrition and mild toxicosis that occurred within 3 wk.

Rapid [14C]heptachlor clearance from body stores of ovines: ingested mineral oil and parenteral trans-stilbene oxide lack effects.

Recently we reported elimination of radioactivity from [14C]heptachlor from body stores of lactating ovines, mainly into excreta rather than milk, contrasting sharply with bovines. To further assess heptachlor metabolism and clearance by ovines, 12 fine-wool wether lambs (41 +/- 3 kg) housed in metabolism stalls were fed pelleted alfalfa hay (96%) plus molasses (3%) ad libitum and were dosed i.p. once with [14C]heptachlor (1.643 mg/kg body wt; sp. act. = .89 microCi/mg). Feces and urine were collected separately and quantitatively. Light mineral oil was mixed with feed (5 g/100 g) of six lambs and trans-stilbene oxide, an inducer of biotransformational enzymes, was administered i.p. (4 g/hd initially; 2 g/hd daily thereafter) through 20 d to three lambs given each mineral oil treatment, in 2 x 2 factorial arrangement. Feces, urine, blood, bile and body tissues were assayed for total 14C activity. Radioactivity (heptachlor and [or] metabolites) eliminated into excreta during 21 d amounted to 34 to 36% of dose administered, of which 67% appeared in urine and 33% in feces. Biological half-time for elimination into excreta was 11.3 d [Kel = -.061/d], similar to 11.7 d we reported for lactating ewes. Clearance from blood had T1/2 = 14 d. Neither mineral oil nor trans-stilbene oxide altered rate or route of 14C activity excreted or concentrations of 14C activity in blood. Results confirmed that ovines eliminate heptachlor much more rapidly than bovines.